Centrifugal pump



CENTRIFUGAL PUMP 6 Sheets-Sheet l Filed Jan. 21, 1965 e s M memmf W Ni M 0 E025 7 VPMM ,7 ma. f A Uf/f f6 5 IQ @r E f SW Y 4/ B p. 8

la, a i a a W12 4/w Y 7 2 o@ Gct. 18, 1966 w. E. RUPP ETAL 3,279,386

CENTRIFUGAL PUMP Filed Jan. 2l, 1965 6 Sheets-Sheei 2 Oct. 18, 1966 w. E. RUPP ETAL CENTRIFUGAL PUMP 6 Sheets-Sheet 5 Filed Jan. 2l, 1965 um. m .6, ,c M Ympi., J 0 Naa LMT @Mp5 v, miam wz VMM Oct. 18, 1966 w. E. RUPP ETAL 3,279,386

CENTRIFUGAL PUMP Filed Jan. 2l, 1965 6 Sheetsm'Sheet 4.

Oct. 18, 1966 w. E. RUPP ETAL CENTRIFUGAL PUMP 6 Sheets-Sheet 5 Filed Jan. 21, 1965 Oct. 18, 1966 w. E. RUPP ETAL CENTRIFUGAL PUMP 6 Sheets-Sheet 6 Filed Jan. 21, 1965 United States Patent O 3,279,386 CENTRIFUGAL PUMP Warren E. Rupp, Mansfield, Stanley B. McFarlln, Jer-omesville, and Charles Edward Young, Jr., Mansfield, h10, assignors to The Gorman-Rupp Company Filed Jan. 21, 1965, Ser. No. 440,044 Claims. (Cl. 103-103) This appliction is a continuation-in-part of our application Serial No. 403,086, filed October 12, 1964, now abandoned.

This invention relates to the centrifugal pump art and is particularly concerned with a self-priming, trash handling, centrifugal pump comprising a new combination of elements, some of which are new, and having a new mode of operation and giving new results.

In prior conventional self-priming centrifugal pumps the inlet pipe opened into the casing well above the impeller and the liquid entered the eye of the impeller in such a way that cavitation resulted with its attendant disadvantages including noise and loss of efiiciency. Accordingly, an important object of the present invention is so to construct and arrange interior parts of the pump as to avoid such cavitation.

Prior conventional centrifugal pumps have been so constructed that the impeller was removable through an opening in the front wall of the casing and the impeller shaft and its bearings were removable through an opening in the back wall of the casing. If, and when, the shaft or its bearings were to be removed, it was necessary to disconnect either the casing or the motor from, and shift it sufficiently on, the foundation to permit removal of the shaft or its bearings through the back wall of the casing. When the casing was shifted it was also necessary to disconnect both the intake and outlet pipes. This manner of assembly and disassembly was costly in labor and down time of the pump. Accordingly, another object of the present invention is to provide a centrifugal pump in which the shaft and its bearings, as well as the impeller, may be removed from the casing without shifting either the casing or the motor on its foundation.

In prior conventional self-priming centrifugal pumps, a check valve has been provided for the intake pipe but such valves have been attached to the pump casing in such a manner that they could be removed for repair or replacement only by disconnecting the intake pipe. This procedure is costly both in labor and down `time of the pump. Accordingly, it is a further object of the present invention to provide a check valve in a self-priming centrifugal pump which can be quickly disassembled from, or assembled with, a pump casing without detaching the inlet pipe.

A further object is to construct a self-priming centrifugal pump embodying all the foregoing advantages.

Other objects of the invention will appear and be pointed out in the following specification.

In the drawings forming a part of the specification,

FIG. 1 is a front elevational view, on a reduced scale of one form of the present invention;

FIG. 2 is a longitudinal, vertical sectional view taken on line 2 2 of FIG. 1 but showing the pump on a larger scale;

FIG. 3 is a fragmentary, vertical, sectional view taken on line 3 3 of FIG. 2;

FIG. 4 is a vertical cross sectional view taken on line 4 4 of FIG. 2;

FIG. 5 is a perspective view of the cover of FIG. 2;

FIG. 6 is a fragmentary, enlarged partly sectional view of a modified form of front cover and ring assembly;

FIG. 7 is a view similar to FIG. 6 but showing another modified form of front cover and ring assembly;

3,279,386 Patented ct. 18, 1966 FIG. 8 is a fragmentary, perspective view of the check valve of FIG. 2;

FIGS. 9 and 10 are fragmentary, sectional views showing modified forms of check valve and securing means;

FIG. 11 is a sectional view, similar to FIG. 2, but showing another embodiment of the present invention;

FIG. 12 is a vertical, transverse, sectional view taken on line 12 12 of FIG. 11;

FIG. 13 is a vertical, transverse, sectional View taken on line 13 13 of FIG. 11;

FIG. 14 is a horizontal sectional view taken on line 14 14 of FIG. 11;

FIG. 15 is a fragmentary, longitudinal, sectional view showing a modified form of the cover assembly of FIGS. 2 and 3; and,

FIG. 16 is a transverse, sectional view taken -on line 16-16 of FIG. 15.

The pump :illustrated in FIGS. l-5 and 8 comprises four main parts, namely, a casing 1, a front cover assembly 2, a rear closure assembly 3 and a check valve assembly 4.

The casing 1 includes a top Wall 6 provided with a threaded fitting 6a for a discharge pipe, a rear wall 7, opposite side walls 8, a front wall 9, botto-m walls 10 and 11 and a drainout trough 12. Partition 13 is substantially vertical and is integral with the top and bottom walls 6, 1!) and 11 and the side walls 8. Rib-like Walls or skids 11a extend upwardly from bottom wall 11 and from front wall 9 to partition 13. The partition 13 partly defines an inlet chamber 15 and a separating cham-ber 17. The midpart includes a circumferential wall 19 which is arcuate in transverse section and partly defines a volute 21. This wall 19 defines axially aligned front and rear openings 22 and 23. A strut 25 connects wall 19 with rear wall 7 and serves to prevent relative movement of these walls.

The front wall 19 is provided with an inlet opening 27, a fitting 29 for attachment to an inlet pipe surrounds this opening Iand is secured to wall 9, as by studs 31 and nuts 32. The front wall 9 is also provided with an opening 34 for the disc 35 of the cover assembly 2 and studs 36 projecting from Ithe front end wall 9 extend through ears 37 on the cover. Nuts Icarried by handles 38 are threaded on studs 36 and secure the cover assembly 3 in position. Gasket 39 around cover 35 serves to prevent escape of liquid through opening 34. Hand grips 40ml on cover 35 and ribs 11a on the casing (FIG. 3) afford means for ready insertion of the cover assembly into the casing and removal from the casin-g. The drain trough 12 is provided with a plug 42 at its front end and opens into the volute 21 and discharge chamber 17 as indicated at 44 and 44a. Thus, fluid may be drained out of both the intake and discharge chambers 15 and 17 through the trough.

The cover assembly 2 comprises -a `disc-shaped cover 35, ring means and rearwardly extending walls in the form of projections 43. The disc 35 is provided with a cylindrical surface sized to fit in opening 34 of front Wall 9 and has a frontend fiange 35b.

The ring means, as shown in FIG. 2, consists of front and rear rings 4t) and 41, which close front opening 22 in partition 13. Ring 41 has a close fit in opening 22 while front ring 40 is slightly larger in diameter than ring 41 and seats against a shoulder 22a in opening 22. Surbstantially vertical projections 43 extend rearwardly from the inner side of cover 35 and are provided with lugs 45 on their remote sides. As clearly appears in FIGS. 3 and 5, these projections are substantially vertical, are arc-shaped in cross section with the convex sides being opposedto each other, and are spaced apart from each other, thereby formi-ng a, vertical space between them through which liquid may fiow vertically and are also spaced apart from the side Walls 8 and the bottom wall 10 thereby affording spaces through which liquid may flow down between each projection 43 and its opposed side wall 48 and upwardly from the bottom wall 10 into the space between the projections. The rings 4t) and 41 are connected to lugs 45 of projections 43 as by studs 47, which are welded to ring 41 and which extend through the rings and the lugs and nuts 49 threaded on the studs.

The ring means, that is, the rings 40 and 41 of FIG. 2, partly dene the pumping lchamber 5l and have central openings 53 which define an inlet into the pumping charn- =ber. When the projections 43 are conne-cted to the ring means, the projections will be positioned on opposite sides of the central openings 53 in the ring means and, hence, will for-n1 downwardly and upwardly converging paths for fluid to flow i-nto the inlet to the pumping chamber.

When the front cover assembly is assembled in the casing and nuts 38 are turned on studs 36, rings 40 will be pressed against the shoulder in partition 13 and flange 35h will be spaced a short distance away from the surface of the front wall 9. Thus, escape of liquid out of the pumping chamber is prevented without the need for a gasket.

In FIG. 6 a modication of the cover assembly and the ring means is shown. In this modication the projections 43 are forme-d integrally w-ith the front ring 40a and the rear ring 41a is provided with studs 40o which extend through holes in the front ring and are held in assembled relation by nuts 4019. In this modification, the lugs 45 of FIGS. 2 and 5 are omitted.

In FIG. 7 a further modification of the cover assembly and ring means is shown. In this modicat-ion, the ring means consists of a single ring 40d integrally connected to the inner ends of the projections 43, the lugs 45 of FIGS. 2 and 5 being omitted.

The rear closure assembly includes several parts. One of these parts is the impeller 55 which is of the single shroud type, that is, it consists of a rear shroud 57 and varies 58, the forward edges 59 of which are positioned closely adjacent to the rear surface of the ring means, the inner ends of vanes 58 partly defining the eye of the impeller aligned with the opening 53 through the ring means.

The axis of impeller 55 is substantially coaxial With opening 22 yin the partition and opening 34 in wall 9 and the diameter of the impeller is slightly less than that of both of these 4openings so that the impeller may be moved axially through both openings.

Other important parts of the rear closure assembly are a cylindn'cal closure, a shaft, bearings for the shaft and a seal ring.

rlhis closure comprises a cylinder 6G which has a ange 62 at its front end anda close tit in the opening 23 in the partition. This flange partly denes the pumping charnber. Sealing means, for example, O-ring 64 around flange 62, seals against the escape of liquid from the pumping chamber through opening 23. The front surface of this flange 62 lies closely adjacent to ,the rear surf-ace of the impeller 5S particularly near i-ts periphery.

Near its rear end closure 60 is provided with ange 65 which engages against the inner surface of rear wall 7 anda cylindrical surface slightly smaller in diameter than the opening `66 through the rear wall 7 of the casing. Means, for example, cap screws 67 extending through wall 7 and into yliange 65 serves t-o hold closure 60 in assembled relation with wall 7. Sealing means, for example, O-ri-ng 72, carried in that cylindrical surface seals .against the escape ot liquid around the closure.

A cylinder 74 is mounted within the closure 60 and at the rear end has a ange '76 attached integrally -to the interior of ythe c-losure 60. Near its forward end, cylinder 74 is integrally connected to closure 6i) by struts 78. The front end of cylinder 74 is closed by a cap 7'5 which is detach-ably connected thereto by screws 75a. The spaces inside and outside of cylinder 74 may be supplied with lubricant through openings which are closed by plugs 79.

Near its forward end cylinder 7-4 carries an antifriction bearing 80, and at its rear end carries another antifriction bearing 81, Vthe shaft 70 being mounted in these bearings.

Seal ring 82 surrounds shaft 70 adjacent to impeller 55 and bears against flange 62 of 4the closure 60 and is secured thereto as by cap screws 84. Seal means 86 are 'ho-used in ring 82 around shaft 7G.

The check valve assembly 4 shown in FIGS. 2 and 8 comprises a disc-shaped body 96 composed of flexible material such as, for example, natural or synthetic rubber and having an integral iiange 97 extending at substantially right angles from the periphery thereto. A disc 98 is secured t-o the rear face of body 96 in any suitable manner, for example as by vulcanizing or bonding, and is of suflicient rigidity to prevent distortion of the body 96 by reason of diierences in pressures applied thereto whe-n the valve is closed. The disc 98 may be made of metal resistant to corrosion in the liquids being handled by the pump. A rigid insert such as metal insert lill is secured in flange `97 and has a hole 103 extending therethrough. As is shown lin FIG. 2 the iitting 29 for an inlet pipe is secured to the front wall 9 of t-he casing and is provided with a rearwardly facing recess 104 in which iiange 97 is seated and held in place by pin 105 which extends through the recess and the opening 103 in insert 4101.

FIG. 9 shows a modified form of check valve assembly. In this form the tting is lin the form -o a at ning L14, preferably 4threaded (not shown) to receive an inlet pipe and is provided with a hole for bol-t 116. The valve consists of a body l117 which may be composed of any of the materials above mentioned With respect to body 96 and has embedded therein a 4rigid disc 118 which serves a purpose similar to that of disc 98. The body has a portion 120 projecting upwardly from its periphery and corresponding to the flange 97 of FIG. 8. The front surface of portion 120 bea-rs against the rear surface of tting 114 and the head of bolt 116 is embedded in said por-tion. A -nut 121 on the outer end of the bolt serves to secure the valve in position within the inlet chamber.

IFIG. lO shows another modied form of inlet valve assembly. In this instance a ring iitting |130, similar to 'ring 114 of FIG. 9, is provided with recess 131 similar to the recess 104 of FIG. 2, and the valve comprises a body l135 with a rigid disc 138 embedded the-rein, both being similar to the construction shown in FIG. 9 of corresponding parts, and the body ,13S has a flange 138 corresponding .to ange .120 of FIG. 8 which projects into recess 131 in ri-ng 130. The head :of bolt 148 is embedded in -the ange 138 and projects through an opening 141 in tting and nut 143 on the outer end of bolt 140 serves to secure the check valve in assembled position.

From the foregoing description it will be understood that the front cover assembly including the ring means may be removed from the casing simply by unscrewing the handle nuts 38 from the studs 36 and pulling the assembly through the opening 34 in the fron-t wall 9` of the casing 1 using handles 40cm for that purpose.V This assembly may be reinsented by reversing this operation. Similarly, it will be understood that after rem-oval of the cover assembly 2, the impeller may be removed Ithrough the front opening 22 in the partition 13 and through the opening 34 in the front wall 9 after disengaging the impeller from the shat. Similarly, the impeller and rear closure may be removed as a unit through the openings 22 and 23 in .the partition 13 and 34 in the front wall 9 of the casing by withdrawing the bolts 67 and moving the complete `assembly .through those openings. Reassembly may be made by Ireversing these operations. The ribs 1:1a serve as skids on which the cover assembly, the impeller and .the rear closure may slide during t-he just described assembly and disassembly operations.

In conventional self-priming centrifugal pumps the inlet chamber extends vertically down from well above the eye of the impeller and opens horizontally into that eye. Due to the force of gravity exerted on the descending liquid and its velocity, a greater quantity of the liquid enters the lower quadrant of the eye of the impeller than enters the upper quadrant and, as a result, the pressure exerted on the liquid in that lower quadrant exceeds that in the upper quadrant. As a result of this lower pressure on the liquid in the upper quadrant, the liquid is thrown out of the upper quadrant with sufficient force to create a condition of vacuum in that space, commonly referred to as cavitation. As the impeller continues to rotate and moves the space downwardly, the liquid rushes in to fill that low pressure space and exerts hammer-like blows on the impeller which result in objectionable noise, deterioration of the impeller, and loss of eiciency. The present invention avoids cavitation and these undesirable results by substantially equalizing the volume and pressure of the liquid entering the upper and lower quadrants of the impeller. This result is achieved by extending the inlet chamber to well 4below the eye of the impeller and employing the projections 43 positioned more or less vertically on opposite sides of the eye -and .apart from the side walls 8 of chamber 15. Such arrangements forms three separate paths for liquid fiow, better shown in FIG. 3, two of the paths being on the outer sides of the projection 43 and the third one being between .the two projections. The force of the liquid flowing down through the passage between projections 43 will .be offset by the fiow of liquid down past the outer sides of the projections and up between them. Thus, as a result there will be a reasonably close balance between the pressures and amounts of uid flowing into the lower and upper quadrants of the impeller eye. Apparently, as a result of this balance the creation of states of vacuum in the impeller is more or less completely avoided, the noise is reduced to a marked extent, the deterioration of the impeller is negligible and the efficiency of the pump is at a maximum.

The pump illust-rated in FIGS. 11 to 14 resembles the pump illustrated in FIGS. 1 to 8 in .that it comprises four main parts, namely, a casing, a front cover assembly, a rear closure assembly and a check valve assembly.

In the following description of FIGS. 1l to 16 and on those figures of the drawing, like numerals are used to designate parts like those in FIGS. 1 to 9 and numerals preceded by numeral 1 are generally like 4the parts in FIGS. l to 9 which bear similar numerals except that the 1 is absent.

The pump illustrated in FIGS. 11 to 14, inclusive, includes a casing 101 having a front cover assembly 102, -a rear closure assembly 103, a check valve assembly 4, a top wall 106 provided with a conventional fitting 106a for a liquid discharge pipe, a real wall 107, opposite side walls 108, a front wall 109, a bottom wall 110 and a drainout plug 142.

The partition 113, which is positioned between rear and front walls 107 and 109, partly denes an inlet chamber 115 and a separating chamber 117. Partition 113 is provided with an opening 22 and with an opening 144 below opening 22. The inlet chamber 115 is also partly defined by the fron-t wall 109 and by downwardly extending opposed walls 116 which are spaced from side walls 108, are connected to partition 113 and front wall 109 and at their lower ends, are arc-shaped as is indicated at 118 and partly define -a cylinder around opening 22. As will be noted, the inlet chamber 115 has considerably less fiuid capacity than that of the chamber 15 in the pump of FIGS. l to 4 and chamber 117 has much greater fluid capacity than chamber 17 of FIG. 2. Also the fact that wall 113 does not extend to walls 108 affords space for liquid flow from chamber 117 into chamber 115, whence it can return to the impeller chamber through opening 144. As a result of such configuration, the casing requires less metal and is less expensive than the casing of FIGS. l to 4 and priming is expedited.

The front wall 109 is provided with an opening 127 and a fitting 129 for attachment to inlet pipe surrounds 6 this opening and is secured to wall 109 by studs 131 and nuts 132.

The cover assembly 102 comprises the disc 135, rearwardly extending, vertical and horizontal walls 143a and 143b, and ring means. The disc 135 is provided with a cylindrical surface sized to fit opening 134 in front wall 109 and has a front iiange 135b, normally out of contact with the front wall 109 but engageable therewith, to limit the rearward movement of the cover assembly.

The front wall 109 is provided with an opening 134 for the disc 135 of the cover assembly 102 and studs 136 project from the front w-all 109 and extend through holes in a bar 137 which is provided with a threaded Arod 138. This rod may be screwed against the disc 135 to force the cover assembly 102 into vassembled position in the casing 101. Bar 137 may serve .as a hand grip by which to move the closure assembly into and out of position in the casing or, if desired, hand grips such -as shown at 40ml in FIG. 2 may be attached to disc 135.

The ring means shown in FIG. 11 includes a front ring 140, preferably integral with the rear ends of walls 143a and 143b, a ring ring 141 which is attached to front ring 140 in any suitable manner, as by studs 149. Ring 140 is slightly larger in diameter than opening 22 through partition 113 and bears against the front side of the partition when the cover closure is in operative assembled position in the casing. Rear ring 141 is slightly smaller in diameter than ring 140 and has a close sliding fit in opening 22 in partition 113. The rear ring 141 partly defines a pumping -chamber and is disposed close to the front edge of the imepller, presently to be described.

It will be noted (FIG. 13) that the walls 143a and 1431; are positioned within the arcuate portions of walls 115 and that walls 14311 in effect constitute continuations of the side walls 1i16 of the linlet chamber. At their lower ends walls 143:1 are disposed adjacent to opposed portions yor ribs 118a of the walls 118 which thereby serve as skids on which the cover assembly may slide when being moved linto or out of position in the casing.

It will also be noted that walls 143a are disposed closely adjacent to the opening 153 through the ring means and into the pumping chamber, and that wall 1435 is disposed below and close to opening 153. As a result of this construction, liquid iiowing past check valve 4 into linlet chamber 115 will ll the space in the cover assembly between walls 143a and 143b and the pressure of `liquid thereabove will insure substantially equal flow of liquid through all parts of opening 153. As a result, cavitation is substantially avoided, as has been described hereinabove with particular respect to the projections 43 of FIGS. 2 and 3.

The rear closure assembly 103 includes an impeller, a rear end closure, bearings and a rear ring.

The impeller 155 is of the single shroud type and has vanes 158 whose front edges are disposed closely adjacent to the rear surface of ring 141. The pumping chamber is partly defined by longitudinally extending walls connected to partition 113 and rear wall 107 and transversely shaped as is better shown in FIGS. 12 and 14 at 156. This longitudinally extending wall not only forms the pumping -chamber 15611 which is partly occupied by impeller 155 but also forms a volute 156b having a discharge outlet 156C well above the pumping chamber.

It will be understood that liquid entering the impeller through opening 153 in the ring means will be propelled by the impeller through volute 156b into the separating chamber 117 whence the liquid, from which some of it, or all the entrained air has escaped, will return downwardly on opposite sides Vof walls 116 and 118 and enter the pumping chamber through opening 144.

The cylinder part 160 of the rear closure has a flange 162 at its front end which has a close fit in opening 164 in rear wall 107 and may be held in assembled relation with the rear wall in any suitable manner, for example, by cap screws i167.

Cylinder 160 has a rear flange provided with bearings for shaft 170 (not shown but similar to parts 68 and '81 of FIG. 2). A cylinder 174 is positioned within cylinder 169 and is integrally connected thereto, as by a rear flange (not shown) and forward struts 178. The front end of cylinder 172 carries a bearing 180 for shaft 170 and is closed by a cap 17S which is detachably connected thereto in any suitable manner. Shaft 170 may be detachably connected at its rear end to means (not shown) for rotating it and is detachably connected at its front end to impeller S. Around the shaft and disposed at the front end of cylinder 160 is positioned a seal ring 182 which is xed thereto, as by cap screws 184, and seal means 186 surrounding and closely adjacent the shaft 170.

It will be seen that the outside diameter of ange 162 on cylinder 160 is slightly less in diameter than `opening 22 in the partition and opening 134 in front wall 109. Thus, the front cover assembly, the impeller and the rear closure assembly including even the shaft may be removed through the front wall of the casing Without disconnecting any pipe connections to the casing or disconnecting connections -of the casing or motor to the door or other support.

FIGS. 15 and 16 show a variation of the cover assembly of FIGS. 1 to 4 which can be used in lieu of the cover assembly of FIGS. 11 to 14. In FIGS. 15 and 16, the cover assembly includes rearwardly extending projections 143e, substantially like those shown at 43 in FIGS. 2 and 3, and a rearwardly extending wall 143611 connected at its front and rear ends to disc 135 and to ring 140. This wall 143d is below the lower edges of projections 143e, and alords space for liquid to pass below those projections. The longitudinal edges of the wall 143s! are disposed closely adjacent to the bottom edges of walls 118. When the cover assembly is to be moved into or out of the casing, the walls 143d will slide on the engaged portions of walls 118 and be supported thereby in such movement.

Having thus described this linvention in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same, and having set forth the best mode contemplated of carrying out this invention, we state that the subject matter which we regard as being our invention is particularly pointed out and distinctly claimed in what is claimed, it being understood that equivalents or modilications of, yor substitutions for, parts of the above specifically described embodiment of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

What is claimed is:

1. A centrifugal pump comprising:

(a) a casing having top, bottom, front and rear walls and substantially aligned openings in said front and rear walls,

(b) an impeller in said casing,

(c) a closure assembly for said opening in the rear wall including a shaft attached to the impeller and means for supporting the shaft for rotation,

(d) a partition disposed between said front and rear walls and partly defining an inlet chamber and `a separation chamber, said partition having an opening aligned with the openings in said front and rear walls and through which opening said closure assembly is movable,

(e) a cover assembly for said opening in the front wall, :said impeller and closure being movable through said opening in the front wall, said cover assembly including a cover having walls extending rearwardly to adjacent to said partition, and ring means positioned in the partition and having an inlet opening into said pumping chamber substantially in alignment with .the axis of rotation of the impeller, said walls of the cover and said ring means being removable through said opening in the front wall of the casing,

(f) and ribs extending rearwardly from the front wall of the casing to the partition below the rearwardly extending wall of said cover, said ribs serving as supports for the cover and rearwardly extending walls during movement thereof into and out of position in said casing.

2. A centrifugal pump comprising:

(a) a casing having front and rear walls and substantially aligned openings in said walls,

(b) an impeller in said casing,

(c) a rear closure assembly including a member closing the opening in said rear wall, projecting into the casing, and having a flange near its inner end partly defining an impeller chamber, shaft bearings in said member, a shaft in said bearings and attached at its inner end to said impeller, and a seal ring engaging the inner end of said member,

(d) a partition disposed between said front and rear walls and partly defining an inlet chamber and a separation chamber, said partition having an opening aligned with the said openings in said front and rear walls and through which opening said rear closure assembly is movable,

(e.) a cover assembly for said opening in the front wall, said impeller and closure being movable through said opening in the front wall, said cover assembly including a cover having walls extending rearwardly to adjacent to said partition, and ring means positioned in the partition and having an inlet opening into said pumping chamber substantially in alignment with the axis of rotation of the impeller, said walls of the cover and said ring means being removable through said opening in the front wall of the casing,

(f) and ribs extending rearwardly from the front wall of the casing to the partition 'below the rearwardly extending walls of said cover, said ribs serving as supports for the cover and rearwardly extending walls during movement thereof into and out of position in said casing.

3. A centrifugal pump comprising:

(a) a casing having front and rear walls and substantially aligned openings in said walls,

(b) an impeller in said casing,

(c) a rear closure assembly including a Imember closing the opening in said rear wall, shaft lbearings in the closure, a seal ring engaging the inner end of the closure, and a shaft rotatably supported in said bearings and attached at its inner end to the impeller,

(d) a partition disposed between said front and rear wall and `partly deining an inlet chamber and a separation chamber, said partition having an opening aligned with the opening in said front and rear walls and through which said rear closure is movable,

(e) a front cover assembly including a cover closing the opening in said `front wall and having rearwardly extending walls, ring means positioned in the partition and attachable to the inner ends of said rearwardly extending walls, said rear closure assembly, said impeller, said ring means and said rearwardly extending walls on the cover being removable through said opening in the front walls of the casing, and

(f) ribs extending rearwardly from the front wall of the casing to the partition Ibelow the rearwardly extending walls of said cover, said ribs serving as supports for the cover assembly during movement thereof into and out of position in said casing.

4. A centrifugal pump comprising:

(a) a casing having front and rear walls and substantially aligned openings in said casing,

(b) an impeller in said casing,

(c) a closure assembly for said opening in the rear wall including a shaft attached to the impeller and means for supporting the shaft for rotation,

(d) a partition disposed between said front and rear walls and a partition defining an inlet chamber and a separation chamber, said partition having an opening aligned with the openings in said front and rear walls and through which opening said closure assembly is movable,

(e) a cover assembly for said opening in the front wall, said impeller and closure being movable through said opening in the front wall, said cover assembly including a cover having walls extending rearwardly to adjacent to said partition, and ring means positioned in the partition and having an inlet opening into the said pumping chamber substantially in `alignment with the axis of rotation of the impeller, said walls of the cover and said ring 'being removable through said opening in the front wall of the casing,

(f) and skid means extending from the front wall of the casing to the partition for slidingly supporting the cover assembly during movement thereof into and out of said casing.

5. A centrifugal pump comprising a casing having a front wall provided with an inlet opening, inlet and outlet chambers and a pumping chamber, impeller means in said pumping chamber, said front wall having an access opening for access to the impeller, an annulus connected to said casing for conducting liquid to said inlet opening,

a check valve having an anchor portion securable to said annulus and a body portion in the inlet chamber and movable relative to the anchor portion for opening and closing the inlet opening, and means extending into said annulus and the anchor portion of the Valve for securing the anchor portion to the annulus, said check Valve being 'bodily movable through said inlet chamber and access opening when said securing means is moved outwardly in the annulus, whereby the valve may Ibe assembled and disassembled without disconnecting the annulus from the casing.

References Cited by the Examiner UNITED STATES PATENTS 1,341,870 6/1920 Woock 137-584 1,502,678 7/1924 Merseles 10.3-103 2,291,760 8/1942 Rupp 103-113 2,386,485 10/ 1945 Longenecker 103-113 2,635,549 4/1953 Rupp 103-113 2,977,042 3/1961 Iassniker 103-111 3,040,669 6/1962 Rupp 103-111 FOREIGN PATENTS 817,077 10/ 1951 Germany.

MARK NEWMAN, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A CENTRIFUGAL PUMP COMPRISING: (A) A CASING HAVING TOP, BOTTOM, FRONT AND REAR WALLS AND SUBSTANTIALLY ALINGED OPENINGS IN SAID FRONT AND REAR WALLS, (B) AN IMPELLER IN SAID CASING, (C) A CLOSURE ASSEMBLY FOR SAID OPENING IN THE REAR WALL INCLUDING A SHAFT ATTACHED TO THE IMPELLER AND MEANS FOR SUPPORTING THE SHAFT FOR ROTATION, (D) A PARTITION DISPOSED BETWEEN SAID FRONT AND REAR WALLS AND PARTLY DEFINING AN INLET CHAMBER AND A SEPARATION CHAMBER, SAID PARTITION HAVING AN OPENING ALIGNED WITH THE OPENINGS IN SAID FRONT AND REAR WALLS AND THROUGH WHICH OPENING SAID CLOSURE ASSEMBLY IS MOVABLE, (E) A COVER ASSEMBLY FOR SAID OPENING IN THE FRONT WALL, SAID IMPELLER AND CLOSURE BEING MOVABLE THROUGH SAID OPENING IN THE FRONT WALL, SAID COVER ASSEMBLY INCLUDING A COVER HAVING WALLS EXTENDING REARWARDLY TO ADJACENT TO SAID PARTITION, AND RING MEANS POSITIONED IN THE PARTITION AND HAVING AN INLET OPENING INTO SAID PUMPING CHAMBER SUBSTANTIALLY IN ALIGNMENT WITH THE AXIS OF ROTATION OF THE IMPELLER, SAID 